1. Field of the Invention
The present invention relates to an information storage medium that records data containing a SYNC code. The present invention also relates to an information recording apparatus for recording data containing a SYNC code on an information storage medium. Furthermore, the present invention relates to an information reproduction apparatus for reproducing data containing a SYNC code from an information storage medium.
2. Description of the Related Art
The DVD format specifies the contents of a SYNC code. In this specification, there are a total of 32 different SYNC codes. The SYNC codes are described in Jpn. Pat. Appln. KOKAI Publication No. 7-254239.
In the existing DVD standard, in order to limit the pit length of a three-dimensional pattern or the maximum mark length of a recording mark (the run length of “0”s allocated between neighboring “1”s in channel bit data), source data undergoes a modulation process based on a specific modulation rule, and the modulated data is recorded on an information storage medium. A modulation method is generally expressed by (d, k; m, n), which symbols mean that “m-bits” source data is converted into data of “n-channel bits”, and a modulated channel bit pattern has a minimum of “d” “0”s run length and a maximum of “k” “0”s run length. That is, the modulated channel bit patterns satisfy conditions that a minimum of “d” pieces of “0”s successively arranged and a maximum of “k” pieces of “0”s successively arranged. The modulation method in the existing DVD standard adopts a (2, 10; 8, 16) method (i.e., “d=2”, “k=10”).
In the next-generation DVD, the recording density is to be further improved. Accordingly, low SYNC code detection precision may pose a problem.